Genotype analysis of hepatitis C virus among blood donors and inmates in Metro Manila, The Philippines

Prevalence of HCV genotypes and subtypes in Southeast Asia: A systematic review and meta-analysis

Known for its high genetic diversity and variation in genotypic presence in different regions of the world, hepatitis C virus (HCV) is estimated to infect about 71 million people globally. Selection of an appropriate therapeutic regimen largely depends on the identification of the genotype responsible for the infection. This systematic review and meta-analysis was conducted to provide a comprehensive view of HCV genotype and subtype distribution in Southeast Asia (SEA). The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). We searched five databases without year and language restrictions. Data from 90 eligible studies involving 15,089 genotypes and 9,646 subtypes representing 10 SEA countries were analyzed. The pooled estimates showed that genotype 1 (46.8%) [95% CI, 43.2–50.4; I² = 92.77%; p < 0.001] was the most dominant HCV genotype in the region, followed by genotype 3 (23.1%) [95% CI, 19.4–27.2; I² = 93.03%; p < 0.001], genotype 6 (16.5%) [95% CI, 13.8–19.6], genotype 2 (4.6%) [95% CI, 3.5–5.9], genotype 4 (1.1%) [95% CI, 0.7–1.5] and genotype 5 (0.8%) [95% CI, 0.4–1.3]. Philippines had the highest prevalence of genotypes 1 and 2. Genotype 6 became more prevalent after year 2000. Over 40 different subtypes were identified, with subtypes 1b (26.3%), 1a (21.3%), and 3a (14.3%) being the most prevalent of all the reported subtypes. Although on a global scale, genotype 6 is considered highly prevalent in SEA, evidence from this study reveals that it is the third most prevalent genotype within the region.

Systematic review: epidemiology and response to direct-acting antiviral therapy in genotype 6 chronic hepatitis C virus infection

BACKGROUND

Hepatitis C virus (HCV) genotype 6 (GT6) is predominantly encountered in Southeast Asia and data on GT6 response to direct-acting antiviral (DAA) therapy are relatively limited.

AIM

To review the epidemiology and virologic outcome of DAA regimens in HCV GT6 patients.

METHODS

Electronic literature search of PubMed, EMBASE, and The Cochrane Library databases were conducted.

RESULTS

Hepatitis C virus genotype 6 is the most genetically diverse, has a prevalence of 19.9%-95.6% in HCV infected patients in Southeast Asia and has been associated with a higher risk of HCC in those with cirrhosis. After an extensive literature review, a total of 20 studies were selected to assess study population and treatment outcomes (total of 938 GT6 patients were included); 12 were clinical trials and eight were observational studies. Sustained virologic response at week 12 (SVR 12) following glecaprevir/pibrentasvir (n = 4; 108 patients), ledipasvir/sofosbuvir (n = 8; 427 patients), sofosbuvir/velpatasvir with or without voxilaprevir (n = 5; 171 patients), sofosbuvir/daclatasvir (n = 3; 172 patients) and sofosbuvir with ribavirin (n = 3; 60 patients) was 98%-100%, 64%-100%, 100%, 88%-94% and 100%, respectively. Failure was mostly in those with cirrhosis and prior treatment experience. DAA therapy was well tolerated and with a serious adverse event rate of <5%.

CONCLUSIONS

Hepatitis C virus genotype 6 is genetically diverse and is highly prevalent in Asia. While SVR rates have been high, cirrhosis and prior treatment experience marginally compromise response to DAAs. Large scale and exclusive studies in HCV genotype 6 prevalent areas are needed, while the current evidence suggests that DAAs are highly effective and safe.

Profile of the VERSANT HCV genotype 2.0 assay

INTRODUCTION

Hepatitis C virus (HCV) is divided into 7 genotypes and 67 subtypes. HCV genotype studies reflect the viral transmission patterns as well as human migration routes. In a clinical setting, HCV genotype is a baseline predictor for the sustained virological response (SVR) in chronic hepatitis C patients treated with peginterferon or some direct acting antivirals (DAAs). The Versant HCV genotype 2.0 assay has been globally used for HCV genotyping over a decade. Areas covered: The assay is based on reverse hybridization principle. It is evolved from its former versions, and the accuracy and successful genotyping/subtyping rate are substantially improved. It shows an accuracy of 99-100% for genotypes 1-6. It can also reliably identify subtypes 1a and 1b. However, the assay does not allow a high resolution for many other subtypes. Reasons for indeterminate or inaccurate genotyping/subtyping results are discussed. Expert commentary: Genotyping helps to find the most efficacious and cost-effective treatment regimen. The rapid development of anti-HCV treatment regimens, however, is greatly simplifying laboratory tests. In the near future, the need for HCV genotyping and frequent serial on-treatment HCV RNA tests will decrease along with the wide use of the more potent and pan-genotypic DAA regimens.

The genetic diversity and evolutionary history of hepatitis C virus in Vietnam

Vietnam has a unique history in association with foreign countries, which may have resulted in multiple introductions of the alien HCV strains to mix with those indigenous ones. In this study, we characterized the HCV sequences in Core-E1 and NS5B regions from 236 Vietnamese individuals. We identified multiple HCV lineages; 6a, 6 e, 6h, 6k, 6l, 6 o, 6p, and two novel variants may represent the indigenous strains; 1a was probably introduced from the US; 1b and 2a possibly originated in East Asia; while 2i, 2j, and 2m were likely brought by French explorers. We inferred the evolutionary history for four major subtypes: 1a, 1b, 6a, and 6 e. The obtained Bayesian Skyline Plots (BSPs) consistently showed the rapid HCV population growth from 1955 to 1963 until 1984 or after, corresponding to the era of the Vietnam War. We also estimated HCV growth rates and reconstructed phylogeographic trees for comparing subtypes 1a, 1b, and HCV-2.

Review article: the epidemiology and therapy of chronic hepatitis C genotypes 4, 5 and 6

BACKGROUND

The global burden of hepatitis C (HCV) infection is mostly found in Africa, the Middle East and Asia, where HCV genotypes 4, 5 and 6 are common. The literature on these genotypes is sparse and this synopsis will review characteristics of patients infected with these genotypes.

AIM

To review characteristics of patients infected with HCV genotypes 4, 5 and 6.

METHODS

PubMed search for 'hepatitis C' AND 'genotype 4', 'hepatitis C' AND 'genotype 5', and 'hepatitis C' AND 'genotype 6' was conducted and relevant articles were reviewed.

RESULTS

Intravenous drug use is generally responsible for HCV genotype 4 infection in developed countries, but unsafe medical practices cause most cases of HCV genotypes 4, 5 and 6 in endemic countries. The sustained virological response (SVR) rate for patients with HCV genotype 4 who receive pegylated interferon and ribavirin for 48 weeks ranges from 40% to 70% in various small studies. The SVR rate is in the 60-70% range for HCV genotype 5 and 70-80% range for HCV genotype 6 following 48 weeks with pegylated interferon and ribavirin. Preliminary data suggest that a shorter course of 24 weeks of pegylated interferon and ribavirin may be acceptable for HCV genotype 6, with an SVR rate of approximately 70%.

CONCLUSIONS

The current standard-of-care therapy for HCV genotypes 4, 5 and 6 is pegylated interferon and ribavirin for 48 weeks. A shorter course with 24 weeks of therapy may be considered for patients with genotype 6. Newer and much more effective therapies may be forthcoming in the next few years.

Systematic review: Asian patients with chronic hepatitis C infection

BACKGROUND

Chronic hepatitis C (CHC) infection is a risk factor for both the development of end-stage liver disease and hepatocellular carcinoma (HCC). Globally, approximately 170 million people are chronically infected with the hepatitis C virus (HCV), and the majority of these individuals come from the western Pacific and Southeast Asia regions (94.6 million persons combined). CHC is an understudied and underappreciated health problem in many Asian countries and in the US, where Asians represent one of the fastest growing groups of new Americans.

AIM

To perform a systematic review of the current literature on the epidemiology, diagnosis and screening, clinical characteristics and response to anti-viral therapy of Asians with CHC.

METHODS

Using a PubMed search of 'hepatitis C' and 'Asia,' 341 original manuscripts published in peer-reviewed journals were identified, and 99 were selected based on their relevance.

RESULTS

Many Asian CHC patients do not have easily identifiable risk factors and may be underdiagnosed. Rates of HCV infection in Asians on community screening in the US are unexpectedly high, and there is a high prevalence of HCV genotype 6 in Southeast Asia and Southern China. HCV-infected Asians tend to present at older age and may have higher risk of HCC; however, they respond better to anti-viral therapy than non-Asians across all HCV genotypes.

CONCLUSIONS

Given the high HCV endemicity in Asia, lack of identifiable risk factors and favourable treatment response rates in Asians, we advocate the screening for HCV infection of all Asians who come from areas where HCV prevalence is ≥2%.

Hepatitis C, hepatitis B and HIV infection among Egyptian prisoners: seroprevalence, risk factors and related chronic liver diseases

BACKGROUND AND AIM

Prisons in Egypt do not currently screen for blood-borne viruses, and there are no statistics concerning the prevalence of hepatitis C virus, hepatitis B virus or human immunodeficiency virus among prisoners. This study was performed to detect the prevalence of antibodies against hepatitis C, hepatitis B core and human immunodeficiency virus among Egyptian prisoners.

METHODS

The study was conducted in an Egyptian prison. The prisoners voluntarily completed a risk factor questionnaire and provided blood specimens for testing for antibodies against hepatitis C virus, hepatitis B virus core antigen and human immunodeficiency virus. Positive results were confirmed by the detecting HCV RNA via polymerase chain reaction. Multivariate regression analysis was performed to determine the factors that were independently associated with positive HCV serology.

RESULTS

Five hundred resident prisoners were screened. The prevalence of hepatitis C virus antibodies was 15.8% (79/500), and viremia was confirmed by PCR in 77.2% (61/79) of the antibody-positive prisoners. The prevalence of antibodies to hepatitis B core antigen was 9.8% (49/500), and 1.2% (6/500) of prisoners were dually infected with HBV and HCV. Antibodies to human immunodeficiency virus were not detected in any of the prisoners. The best predictor for hepatitis C and hepatitis B infection was a history of intravenous drug use (P<0.011 for HBV and P<0.001 for HCV), a period of >10 years spent in prison (P<0.052 for HBV and P<0.021 for HCV) and shared toiletries (P<0.059 for HBV and P<0.002 for HCV).

CONCLUSION

Hepatitis C and hepatitis B virus infections constitute an important public health problem in prisons. Public health strategies to prevent morbidity and mortality from these infections should include hepatitis B vaccination, HCV testing, counseling and medical management of infected prisoners.

The prevalence of HIV, HBV and HCV among Filipino blood donors and overseas work visa applicants

OBJECTIVE

Our aim was to estimate the prevalence of HIV, HBV and HCV among the general population of the Philippines using data sources outside of the limited existing active surveillance network.

METHODS

We analysed aggregate HIV, HBV and HCV test results for hospital-based blood donors (BDs) and overseas Filipino worker candidates (OFWCs) that had been reported from licensed laboratories to the National STD/AIDS Cooperative Central Laboratory in Manila between 2002 and 2004.

FINDINGS

From over 144 000 blood-screening results, the HIV prevalence was 0.006% in BDs and 0.001% in OFWCs; that of HBV was 4.2% in both groups; and that of HCV was 0.3% in BDs and 0.9% in OFWCs. Males were at increased risk of both HBV and HCV; among OFWCs, younger women were at increased risk. Laboratories that tested sequentially but stopped testing after the first positive result were far less likely to detect HCV, indicating that sequential testing protocols may underestimate HCV and HIV prevalence. OFWCs were at low risk of HIV, and the risk of testing positive for these viruses was not increased among OFWCs applying for a repeated work visa, compared with first time-applicants.

CONCLUSION

Based on these data, we conclude that HIV is rare in the Philippines. In contrast with prior reports, we found no evidence that OFWCs constitute a high-risk group for HIV. Further research is needed to understand why younger women are at increased risk of acquiring HBV.

A natural inter-genotypic (2b/1b) recombinant of hepatitis C virus in the Philippines

The prevalence study and the characterization of hepatitis C virus (HCV) was carried out in the Philippines and the sequence determination of the 5'-untranslated region (5'-UTR)-Core and the NS5B regions of HCV was carried out in this study. An HCV strain (SE-03-07-1689) collected in Metro Manila, Philippines, belonged to discordant subtypes, 2b and 1b in 5'-UTR-Core and NS5B regions, respectively. The 9.3 kb sequence of this strain including the entire open reading frame was compared with those of the reference strains retrieved from the HCV sequences database (GenBank/EMBL/DDBJ) and indicated a recombination event. The computation of the sequence similarity mapped a crossover point within the NS3 region. This is the second report on the inter-genotype recombinant of HCV and the third when an intra-genotype recombinant is included. This recombinant strain, SE-03-07-1689, is designated tentatively as RF3_2b/1b according to the suggestions used for the other two HCV recombinants.

Distribution of hepatitis C virus genotypes in the Middle East

It is well established that hepatitis C develops into cirrhosis of the liver and hepatocellular carcinoma (HCC) both of which are fatal diseases. The World Health Organization estimates that there are at least 21.3 million hepatitis C virus (HCV) carriers in the Eastern Mediterranean countries, which is close to the number of carriers estimated in the Americas and Europe combined. With such a high disease burden of HCV infection in this part of the world, and in light of the new evidence that genotypes may influence the outcome of antiviral therapy, the focus of this review is on the epidemiology and distribution of HCV genotypes in the Eastern Mediterranean countries. Accumulated data show that there are two main patterns for the distribution of HCV genotypes in the Middle East: in the first pattern, genotype 4 is prevalent in most of the Arab countries, and in the second pattern, genotype 1a or 1b predominates in the non-Arab countries. Results from the limited number of clinical trials on the treatment of chronic HCV genotype 4 using peginterferon alfa-2b in combination with ribavirin are encouraging. However, efforts to develop more effective antiviral therapies and the establishment of an effective HCV vaccine remain the largest challenges for the near future.

Chronic hepatitis C: genotypes 4 to 9

Infection with hepatitis C virus (HCV) genotypes 1, 2, or 3 is widely distributed throughout the world and has been the focus of the majority of studies on the epidemiology and treatment of chronic hepatitis C. Infection with HCV genotypes 4 through 9 is prevalent in some geographic areas where the disease burden of chronic hepatitis C approaches endemic levels (eg, HCV genotype 4 in Egypt where there is an HCV infection prevalence of approximately 18%). This article reviews the existing literature, which suggests that chronic hepatitis C with genotypes 4 through 9 may exhibit epidemiologic, clinical, and treatment outcome differences from infection with genotypes 1, 2, or 3.

Rapid spread of hepatitis C virus among injecting-drug users in the Philippines: Implications for HIV epidemics

From the trends of human immunodeficiency virus (HIV) epidemics in South and Southeast Asia, it was postulated that an HIV epidemic would start as a blood-borne infection among injecting-drug users in the Philippines. In 2002, 560 individuals were recruited in Metro Cebu, Philippines and tested for HIV, hepatitis C virus (HCV), and hepatitis B virus (HBV) infections. The seroprevalence of anti-HCV among injecting-drug users (70.1%, 61/87) was significantly higher than those among inhalation drug users (16.3%, 7/43; P = 0.00; OR = 12), sex workers (0%, 0/130; P = 0.00; OR = infinity), antenatal clinic attendees (0%, 0/100; P = 0.00; OR = infinity), and students/health care workers (2%, 4/200; P = 0.00; OR = 115). The seroprevalence of HBsAg among injecting-drug users (10.3%, 9/87) was significantly higher than those among sex workers (2.3%, 3/130; P = 0.01; OR = 4.9), and antenatal clinic attendees (3%, 3/100; P = 0.04; OR = 3.7), but was not statistically different from those among inhalation drug users (9.3%, 4/43; P = 0.9) and students/health care workers (4.5%, 9/200; P = 0.06). None of the study population was reactive to anti-HIV antibody. The HCV strains obtained from the injecting-drug users belonged to either genotype 1a or 2b and the strains in each genotype clustered closely to each other. There was no dual infection with genotype 1a and 2b. These results suggest that the HCV infection in injecting-drug users may be emanating rapidly from limited number individuals in Metro Cebu, Philippines.

Public health challenges in hepatitis C virus infection

The discovery a decade ago of the hepatitis C virus (HCV) led to control of post-transfusion hepatitis in many countries, but raised a number of further questions about the transmission and epidemiological distribution of the newly discovered virus. In some countries, the diagnosis of HCV infection has been designated as a notifiable condition, with doctors (or laboratories, or both) required to send case reports to public health authorities. Such case reports of HCV diagnosis are inevitably biased towards people with symptomatic presentations or a known history of exposure, or those who undergo screening for other purposes, such as blood transfusion. Another approach has been the use of serological prevalence surveys either making use of blood that had been taken or tested for other purposes or recruiting specific population groups for the explicit purpose of measuring HCV prevalence. A limited number of surveys have either attempted to obtain true random samples of geographically defined populations, or recruited subjects, such as pregnant women, who may be considered to be broadly representative of the wider population. Injecting drug use is clearly the main mode of HCV transmission in countries that have established comprehensive blood screening, and it remains a major public health challenge. Although mother-to-child transmission is known to occur with a frequency of about 7% there is no proven means of prevention and very little is known about the long-term consequences of maternally transmitted infection. The conclusion from a number of somewhat conflicting studies is probably that HCV infection should not be viewed as a sexually transmissible infection from the perspective of population health strategies. However, people with HCV infection and their sexual partners should minimize the extent of blood contact that may occur through sexual activity.

Differential prevalence of hepatitis C virus subtypes in healthy blood donors, patients on maintenance hemodialysis, and patients with hepatocellular carcinoma in Surabaya, Indonesia

Determination of the prevalence of liver disease caused by hepatitis C virus (HCV) of various genotypes helps provide an understanding of the virulences of these genotypes. Differences in the prevalences of these genotypes are known to exist in the various geographical regions of the world. Hence, we performed seroepidemiological and molecular epidemiological analyses of HCV in Surabaya, Indonesia. The prevalences of anti-HCV antibodies were 2.3, 76.3 and 64.7% in healthy blood donors, patients on maintenance hemodialysis, and patients with hepatocellular carcinoma (HCC), respectively. HCV-2a was the most common (52%) among the HCV clones obtained from blood donors; this was followed by HCV-1b (15%), HCV-1a (7%), and HCV-1d (7%), a unique Indonesian subtype. The high prevalence of HCV-2a in blood donors was further supported by serotyping analysis that could discriminate HCV type 2 (HCV-2a and -2b) from HCV type 1 (HCV-1a, -1b, and -1d). HCV-1a, -1b, and -1d were strongly associated with elevated serum alanine aminotransferase (ALT) levels in blood donors, suggesting a possibly more pathogenic feature of those subtypes than HCV-2a. In patients on maintenance hemodialysis, HCV-1a and -1b (each 31%) were among the most common subtypes, and in contrast to the case with blood donors, HCV-1a, -1b, and -1d were found in those with normal ALT as well as those with elevated ALT levels. Impaired immune responses of hemodialyzed patients might be responsible for the apparently decreased hepatocytic injury caused by infection with HCV type 1. In patients with HCC, HCV-1b (57%) was the most common; this was followed by HCV-1d (19%) and HCV-2a (5%). Subtype prevalence was not different between HCC patients with advanced liver cirrhosis and those without advanced cirrhosis.